What is the term for the sum of money invested or loaned that the interest applies to?

The term for the sum of money invested or loaned that the interest applies to is "Principal." In financial contexts, the principal amount is the initial size of a loan or investment before interest is applied. Understanding the concept of principal is crucial for calculating interest and returns on investments.

In loans, the principal is the amount borrowed that must be repaid, while in investments, it refers to the original capital that earns interest or dividends over time. This distinction is essential in finance because the total amount paid back or earned will depend significantly on this principal amount.

The other terms presented do not relate to the core concept of an amount that interest applies to. Dividends refer to payments made to shareholders from a corporation's earnings, revenue is the total income generated by a business before any expenses are paid, and an asset refers to anything of value owned by an individual or business. Each of these terms operates in different financial contexts and does not directly address the amount subject to interest.